# CVE-2026-90778: SIPp buffer overflow in get_peer_tag() function

Source: https://junglewise.ai/threats/cve-2026-90778-sipp-buffer-overflow-in-get-peer-tag-function  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-13. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-90778 · Severity: high · CVSS 7.5 · Published 2026-09-13

SIPp is a widely-used testing tool for Session Initiation Protocol (SIP) applications. The tool contains a buffer overflow vulnerability in its SIP message parser that can be triggered by sending a specially crafted message with an oversized tag parameter. An unauthenticated attacker on the network can exploit this to crash the SIPp process, causing testing services to become unavailable.

Technologies: [SIPp](https://junglewise.ai/threats/technologies/sipp). Vendors: [SIPp](https://junglewise.ai/threats/vendors/sipp).

## Quick answers

**Is CVE-2026-90778 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-90778 being exploited in the wild.

**How severe is CVE-2026-90778?** High severity, with a CVSS score of 7.5, published 13 September 2026.

**Which products and versions are affected?** SIPp through 3.7.7.

**Is there a fix for CVE-2026-90778?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-90778 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-90778?** Check whether you run SIPp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a classic stack-based buffer overflow in the get_peer_tag() function within the SIP parser (sip_parser.cpp). The function fails to properly validate the length of the tag parameter in SIP To headers, allowing an attacker to write beyond the bounds of a static buffer when processing tag parameters of 2049 bytes or more. The attack requires no authentication and is triggered by sending a single crafted SIP message over the network. Successful exploitation results in process crash (denial of service); remote code execution is theoretically possible depending on memory layout and compiler protections. Patches are expected to be available in versions after 3.7.7.

## Affected products

- SIPp SIPp through 3.7.7

## Timeline

- 2026-09-13: disclosed

## References

- [https://github.com/SIPp/sipp](https://github.com/SIPp/sipp)
- [https://github.com/SIPp/sipp/blob/v3.7.7/src/sip_parser.cpp](https://github.com/SIPp/sipp/blob/v3.7.7/src/sip_parser.cpp)

## Related threats

- [SIPp buffer overflow in get_header function](https://junglewise.ai/threats/cve-2026-90780-sipp-buffer-overflow-in-get-header-function)
- [SIPp stack buffer overflow in createAuthHeader()](https://junglewise.ai/threats/cve-2026-90779-sipp-stack-buffer-overflow-in-createauthheader)
- [SIPp buffer overflow in command-line argument handling](https://junglewise.ai/threats/cve-2018-25356-sipp-buffer-overflow-in-command-line-argument-handling)